Food and Digestion Why do we need to

Food and Digestion

Why do we need to eat? What is a healthy diet? What are the 5 essential nutrients?

What is “Food” and what is “Nutrition”? Food is any edible material that supports growth, repair and maintenance of the body. Food also protects the body from infections and diseases. Nutrition is the process by which body utilizes food for growth and maintenance and healthy living. Food functions in the body through the nutrients it contains

• What food does in the body does through the nutrients it contains. The body utilizes these nutrients to grow and keep healthy and strong. All nutrients needed by the body are available through food. • No food by itself (except for breast milk which is adequate for babies up to six months of age) has all the nutrients needed for full growth and health. Food therefore must be balanced. • We therefore need a variety of foods to get all the nutrients the body needs • Each nutrient has its own function in the body. • Specific nutrients do their best work in the body when present with other nutrients. • Nutrients are therefore mutually supportive.

What are Macronutrients and Micronutrients? The nutrients can be divided into two major groups – “Macronutrients” and “Micronutrients”. Macronutrients are those that are needed in large quantities (tens or hundreds of grams) every day. These are: Carbohydrates, protein and fats/oils. Micronutrients are those that are needed in minute quantities (micrograms or at best milligrams). These are vitamins, minerals and trace elements.

Nutrients 1. What are nutrients? • Essential substances that your body needs in order to grow and stay healthy • Six categories of nutrients: • Carbohydrates • Proteins • Minerals • Vitamins • Fats • Water

Carbohydrates • Structure and function: • the term carbohydrate is derived from the French: hydrate de Carbone • compounds composed of C, H, and O • Carbohydrates are sugars and starches that the body uses for ENERGY! • PLANTS are the major source of carbohydrates in the food we eat. • They can be classified as: © 2005 Jupiter. Images Corporation

Simple Carbohydrates • Sugars that are quickly digested and provide a BOOST of energy for the body • Foods with LOTS of sugar: Glucose, fructose… ( oranges, milk, cookies, candy)

Complex Carbohydrates Starches that are • Foods with composed of many • LOTS of starch: sugars linked rice, yam, together wheat, potatoes • They provide the body with long-term energy since they are digested more slowly than sugars.

During well-fed conditions, body glucose is stored in liver and muscles as glycogen, a compound carbohydrate. Glycogen is therefore the animal counterpart of plant starch. During starvation, glycogen of liver and muscle is broken into glucose to provide energy. Glucose is the only fuel for the brain under normal conditions. Carbohydrates taken in excess of energy requirements are directly converted into fat and deposited in the body. Compound carbohydrates are polymers of glucose.

Carbohydrates and sugars Digestion in the intestine Glucose (plus other monosaccharide) Absorbed into blood In presence of insulin Taken up by cells In presence of O 2 Metabolized to CO 2 + H 2 O + Energy (no side effects in glucose use in the body)

Protein • Structure: Proteins are made from many amino acids connected together in different arrangements. • Function: Provide the building materials your body needs to grow and repair itself. • There are 2 types of amino acids present in proteins:

Essential Amino Acids • 9 of the 20 amino acids are called essential amino acids because you must obtain them from the foods you eat since your body cannot make them.

Non-Essential Amino Acids • Since the body can synthesize these amino acids it is not essential or important to make them a part of your diet. • Proteins can also be classified based on their biological value:

Complete proteins: • Foods containing all the essential amino acids Examples: fish, meat, eggs, milk, cheese… in short animal source proteins. Incomplete proteins: • Foods that are missing some essential amino acids Examples: Legumes, nuts, whole grains… most of the plant source proteins.

Protein Digestion in the gastro-intestinal tract Amino acids Absorbed into blood Taken up by the cells Synthesize body proteins

Structure: Fat they are also made of C, H and O. they are broken down to fatty acids and glycerol. Fats belong to a group of organic compounds called lipids which are substances that do not dissolve in water. Functions: • • • ENERGY source for the body (more than carbs and proteins) Help protect and cushion vital organs as well as joints Insulate the body

Fat provides the building materials for some body parts, such as brain, nerves and hormones. It also facilitates absorption, transport and storage of fat-soluble vitamins A, D, E and K. Fat is therefore an essential nutrient. Like all other nutrients, fat is beneficial if consumed in the right amount and if it is the right type. Since high blood cholesterol is a risk factor for coronary heart disease, diet rich in preformed cholesterol and saturated fat is to taken with caution after a certain age. It is, however, not a problem for infants and young growing children.

They can be classified into 2 types Saturated fats: • Contain fatty acids with the MAXIMUM amount of hydrogen atoms • At room temperature, they are typically in solid form.

Unsaturated fats: • • Contain fatty acids that are missing hydrogen atoms • • At room temperature, they are typically in liquid form. They are less harmful to the circulatory system than saturated fats. Foods with a lot of unsaturated fat: canola, safflower, and peanut oils

• Diets with TOO MUCH saturated fat have been known to cause heart disease. • Foods with a lot of saturated fat: beef fat, egg yolks, dairy products

Calories What is a calorie? • The energy obtained from carbohydrates, proteins, and fats is measured in units called calories.

Calorie Calculations • Carbohydrates 1 g = 4 calories • Protein 1 g = 4 calories • Fat • Alcohol 1 g = 9 calories 1 g = 7 calories

Sample Calculation • A slice of bread has 9 g of carbohydrates, 2 g of protein, and 1 g of fat. • Get out a piece of paper and see if you can do the calculations…. .

• 9 grams carbohydrates x 4 calories/gram = 36 calories + 2 grams protein x 4 calories/gram = 8 calories + 1 gram fat x 9 calories/gram = 9 calories _____________ Total calories = 53

Do you know the MOST IMPORTANT nutrient? It’s Water! • 60%-80% of the human body is WATER!

• Function: • Assists with the transport of materials in the body by making up most of the liquid part of blood (plasma), helps regulate body temperature, and helps break down food in the digestive system • Food sources: • vegetables, fruit, milk

Micronutrients • Minerals and vitamins are called micronutrients since they are needed by your body in SMALL amounts. The minerals and most of the vitamins your body needs must be obtained from the FOODS you eat since your body cannot make them.

Micronutrients: Minerals • Minerals are INORGANIC substances that are required by your body in order to develop and grow properly. Some Important Minerals: • Calcium Iron • Potassium Magnesium

Macro Minerals Calcium • Function: Helps build strong bones and teeth, regulates blood clotting • Food sources: dairy products, leafy and green vegetables.

Macro Minerals Iron • Function: Helps build hemoglobin which is the oxygen-carrying part of your red blood cells • Food sources: eggs, meats, whole grains • Deficiency disease: Anemia

Macro Minerals Potassium • Function: Helps regulate fluid balance in the body, assists with the normal functioning of muscles and nerves • Food sources: bananas, carrots, milk

Macro Minerals Magnesium • Function: Involved in the metabolism of proteins and carbohydrates, assists with bone growth and proper muscle functioning • Food sources: milk, meat, nuts

Micro Minerals iodine: • Function: Needed for your thyroid gland to function properly • Food sources: Seafood, Iodized salt (salt that has had iodine added to it), Drinking water (in regions with iodine-rich soil, which are usually near an ocean • Deficiency disease: Goiter.

Some of the key roles of minerals are shown in the table below. Mineral Function Calcium Mineralization of bones and teeth; regulator of many of the body’s biochemical processes; involved in blood clotting, muscle contraction and relaxation, nerve function, blood pressure and immune defenses Phosphorous Mineralization of bones and teeth; part of every cell; used in energy transfer and maintenance of acid-base balance Sodium Maintains normal fluid and electrolyte balance, assists nerve impulse initiation and muscle contraction Chloride Maintains normal fluid and electrolyte balance Chromium Works with insulin and is required for release of energy from glucose Copper Necessary for absorption and use of iron in the formation of hemoglobin

Fluoride Involved in the formation of dental enamel and prevents dental caries; involved in the formation of teeth and skeleton and inhibits osteoporosis in old age Iodine As part of the two thyroid hormones, iodine regulates growth, physical and mental development and metabolic rate Iron Essential in the formation of blood; involved in the transport and storage of oxygen in the blood and is a cofactor bound to several non-heme enzymes required for the proper functioning of cells Sulfur Integral part of vitamins, biotin and thiamin, as well as the hormone insulin Zinc Essential for normal growth, development, reproduction and immunity Magnesium Involved in bone formation and tissue energy metabolism

Micronutrients: Vitamins Group of complex compounds that help your body maintain normal metabolism, growth, and development Two Groups of Vitamins: • Water-Soluble • Fat-Soluble

Micronutrients: Vitamins Water-Soluble Vitamins: • Vitamins that dissolve in water and are NOT stored in your body for future use Vitamin B complex and Vitamin C

Examples of Water-Soluble Vitamins: • Vitamin C: Fights against infection, maintains healthy gums, strengthens and maintains blood vessel structure – Food sources: citrus fruits, tomatoes, leafy vegetables

Micronutrients: Vitamins Vitamin B Complex: Helps prevent birth defects, and is needed in the formation of red blood cells and nucleic acids – Food sources: beets, broccoli, avocado, turkey and lentils. – Deficiency diseases: Beriberi(VB), Pellagra(VB 4), Pernicious Anemia (VB 12)

Micronutrients: Vitamins Fat-Soluble Vitamins: • Vitamins that dissolve into and are transported by fat • They can be stored in fat tissue, the liver, and the kidneys. • Vitamins A, D, E, and K

Examples of Fat-Soluble Vitamins: • Vitamin A: Maintains good vision, promotes body cell growth, helps protect teeth –Food sources: green vegetables, dairy products –Deficiency disease: Night Blindness, Xerophthalmia.

• Vitamin D: Promotes the development of healthy bones and teeth – Food sources: eggs, salmon, fortified breakfast cereal. Other sources include sunlight. – Deficiency diseases: Rickets (in children) osteomalacia (in adults)

(vitamin B 1) (vitamin B 2) V B 4 (Vitamin B 6) Folic acid Function Rich sources Helps release energy from nutrients; supports normal appetite and nerve function Cereal grains, pulses, yeasts; Helps release energy from nutrients; supports skin health; prevents deficiency manifested by cracks and redness at corners of mouth, inflammation of the tongue and dermatitis Helps release energy from nutrients; supports skin, nervous and digestive systems Milk and its non-fat products; Helps make red blood cells; helps in amino acid and fatty acid metabolism Widely present in both plant and animal foods Helps in the formation of DNA and new blood cells including red blood cells; prevents anemia, some birth defects, heart disease Green vegetables, fish, meat, fruit, milk Green vegetables, meat, fish, egg Liver, ground nuts, cereal bran or germ Dark-green leaves, liver, kidney

Vitamin C Vitamin A Vitamin D Vitamin E Helps in the formation of protein, collagen, bone, teeth, cartilage, skin and scar tissue; facilitates the absorption of iron from the gastrointestinal tract; involved in amino acid metabolism; increases resistance to infection Fruits, vegetables and dark-green leaves Maintains normal vision, skin health, bone and tooth growth, reproduction and immune function, prevents xerophthalmia Animal sources: Butter, eggs, milk, liver; Plant sources: Dark-green leafy vegetables, mangoes, papaya, tomato Helps in the mineralization of bones by enhancing absorption of calcium Fish liver oils, eggs, cheese, milk and butter; Sunlight induces synthesis of vit. D in the body from skin cholesterol. Strong antioxidant; helps prevent atherosclerosis; protects neuromuscular system; important for normal immune function Vegetable oils, germinated whole-grain cereals

Vitamin C Vitamin A Vitamin D Vitamin E Helps in the formation of protein, collagen, bone, teeth, cartilage, skin and scar tissue; facilitates the absorption of iron from the gastrointestinal tract; involved in amino acid metabolism; increases resistance to infection Fruits, vegetables and dark-green leaves Maintains normal vision, skin health, bone and tooth growth, reproduction and immune function, prevents xerophthalmia Animal sources: Butter, eggs, milk, liver; Plant sources: Dark-green leafy vegetables, mangoes, papaya, tomato Helps in the mineralization of bones by enhancing absorption of calcium Fish liver oils, eggs, cheese, milk and butter; Sunlight induces synthesis of vit. D in the body from skin cholesterol. Strong antioxidant; helps prevent atherosclerosis; protects neuromuscular system; important for normal immune function Vegetable oils, germinated whole-grain cereals

Task-4 Sl. Type no : 1 Vitamin A 2 Vitamin B 1 3 Vitamin B 4 4 Vitamin B 12 5 Vitamin C 6 Vitamin D 7 Vitamin E 8 Vitamin K Functions Deficiency disease Symptoms Rich food sources

Dietary Fiber Dietary fibers are non-digestible, nonabsorbable components of food. • • Fibers form the bulk of the stool and help in clearing the bowel and in preventing constipation and colon cancer. • Fibers inhibit absorption of glucose and cholesterol from the GI tract, thus are helpful in diabetes and heart disease. • Fruits, vegetables, pulses and whole cereals are sources of dietary fiber. • Our daily diet should contain some fiber for good health and well being.

Non-nutrient components of health significance Some plant foods show additional health benefits beyond basic nutrition. These foods are called “Functional Foods”. • • These ingredients protect our body from various diseases like diabetes, hypertension, and some forms of cancer. • Bright examples of functional foods are tomatoes, mushroom, apple and guava, garlic, onion, ginger, clovesandotherspices, cabbage, cauliflower, broccoli, blackberry, and tea. • The above functional foods should be a part of our daily dietary.

A Balanced diet • A healthy diet involves consuming appropriate amounts of all nutrients and an adequate amount of water. Nutrients can be obtained from many different foods, so there a wide variety of diets that may be considered healthy diets. A healthy diet needs to have a balance of macronutrients / energy ( fats, proteins, and carbohydrates ) and micronutrients to meet the needs for human nutrition without inducing toxicity from excessive amounts.

Keep in mind… • • Balanced diet varies with Age Gender occupation Weight control diets To prevent cancer Against hypertension

Task-6 • In groups of 3 , design an ideal menu for • the age groups: 3 -12, 13 -23, 24 -50, 50 and above • justify your design (40 min). • Resource sites: • http: //www. sambal. co. uk/diet. html • http: //www. ifood. tv/blog/choose-a-balanceddiet-for-children

Food Processing

Food Processing • Most food consists of what macromolecules? – Carbohydrates, lipids, and proteins • Why is food chemically broken down? – The macromolecules are too large to pass through cell membranes – The polymers must be broken down into monomers, so that the organism can make their own polymers